Extension ladder



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Patented Apr. 21, 1936 UNlTED STATES,

EXTENSION LADDER Wilhelm Adolf Hummel,

Ulm-on-the-Donau,

Germany, assignmto firm C. D. Magirus Aktiengesellschait, Ulm-on-the-Donau, Germany Application July 20, 1931, Serial 110.552.018

Germany July 23, 1930 9 Claims. (Cl. 228-18) braces therein, or combine several sections in such' manner that they brace each other.

Sections according to-my invention have the advantage that they are not only strong against compression, tension and bending at right angles to the plane 01' the units but also against bending moments in the plane of the units and against torsion.

It is another object of my invention to eliminate unsymmetrical tensions in the sections of the side pieces to which end the side piece sections are made symmetrical to their central vertical plane.

It is still another object of my invention to provide a particularly simple design of the side pieces. To this end I built up the side pieces from an upper and a lower flanged section, of U or V shape, and a horizontal brace between the flanges which is preferably welded thereto. The

flanges serve also for guiding the several telescoping units of the ladder with respect to each other.

Any other sections may be used for building up side pieces and other parts of the units A particularly favorable section with regard to strength and stiffness of its side pieces is'one that has the shape of a T, with one or more bracings in its central plane at right angles to the plane of the unit.

A section which is particularly favorable with respect to the guiding or the units is obtained by combining sections resembling the letters 8 or Z. with box girders as the bars of thes or Z sections,

and the horizontal girders equipped with rollers for guiding the units.

The rungs of the units may also be made 01! sections which may be open or closed and are readily connected to the sides or the flanges of the sidepiece sections so as to be stifiagainst bending and torsion, for instance, by welding.

It is still another object oi my invention to provide improved means for bracing the side pieces. To this end I design the bracing means like lattice work built up from closed hollow sections, and

arrange them preferably symmetrically to the central vertical'plane of the side-piece sections.

It is still another object of my invention to provide improved means for guiding the telescoping units with respect to each other, as will be described.

In the accompanying drawings various ladders embodying my invention are illustrated diagrammatically by way of example.

In the drawings Fig. 1 is an elevation of a truck having an extension ladder of four units.

Fig. 2 is a rear end elevation oi the truck,

Fig. 3 is a section at right angles to the side pieces of a ladder showingfside pieces built up from flanged V sections,

Figs. 4 and 5 are sections on and VV in Fig.3,

Fig. 6 is an elevation showing part of the lattice work for bracing the side pieces,

Fig. '1 is a section on the line VII-VII in Fig. 6,

Fig. 8 is a cross section 01' three units having side pieces built up from two channel sections each to form a double T, or I,

Fig. 9 is a section on the line IXIX in Fig. 8 in which the upper part of the ladder is not shown in order to save space,

Figs. 10, 10a, and 10b show sections of modified double-T side pieces,

Fig. 11 is a cross section of three units having the lines IV-IV side pieces built up from trapezium sections,

Fig. 12 shows a modified trapezium section,

Figs. 13 and 14 show two types of rectangular sections,

Fig. 15 is a section on the line XV-XV in Fig. 11 in which the upper part of the ladder is not shown in order to save space,

Fig. 16 is a cross section of three units having 2 shaped side pieces from three box girders,

Fig. 17 is a section on the line XVII--XVII in Fig. 16 in which the upper part of the ladder is not shown in order to save space,

Figs. 18 and 19 show modified Z sections,

Fig. 20 .is an elevation showing part of two units, with rocking guide rollers,

Fig. 21 is, a section on the line XXIXXI in Fig. 20,

Fig. 22 is an eleva ion showing two of the rocking rollers, with their supporting arm,

Fig. 23 is a section on the line XXIII-XXIII in Fig. 22, and

Fig. 24 shows two more rocking rollers,

Referring now to the drawings, and flrst to Figs. 1 and 2, A is the ladder in collapsed condition, and B is the truck on which it is carried. C, D, E, F are its four telescoping units, each with a pair of side pieces, and pillars l6, diagonals 20, and a hand rail l9 per side piece.

Referring now to Figs. 3 to '7, l are the side pieces at oneside of the tour telescoping units. The lowest side piece comprises a flanged V section 2 which may be rolled or pressed, and a stay 5 secured to the flanges 3, 4 of the inverted V section 2. I2 is a bearing sleeve, which is secured in the section 2 by welding or in any other suitable manner, H is a pin in the sleeve, I0 is a roller on the pin, and I3 is a bearing for the free end of the pin which is welded, or otherwise secured to, the bottom plate of a rung H, as best seen in Fig. 5. The top of the rung is supported by a tubular transverse stay 33. The side pieces of the units above the lowest unit are equipped with channel sections l below the stays oi their sections with their flanges ti and welded or otherwise secured to-the stay The channel sections '1 are races for the rollers it. Obviously I not limited to channel sections, but may provide V or flat tubular sections etc. instead. The units are held in position in upward direction by checks ll at the apices of the v sections 2, and by rollers l5 on pins 88 in the pillars Ill. The checks l? are angular and lined with wear plates l8 opposite depending portions at the inner sides of the stays 5, or the flanges 3 or 8. The checks ll have inwardly projecting flanges ll.

The sections from which the sidepieces are built up may be made in any suitable manner, for instance, by being rolled or by being drawn from separate bars or as a single bar.

The hand rail l9, Fig. 6,'the pillars l6 and the diagonals 20 are also made of hollow sections like the side pieces I, in order to increase their compression strength.

hollow channel sections 22, 23, and a stay 24 placed centrally between them. The'stay is preferably welded to the sections 22, 23.

The side pieces are held against displacement in vertical direction by the interlocking of the flanges 28, 29 of the Ts, and supported on rollers 30 which are seated on the pins l I. The pins are held in sleeves 3| of the sections, at one end, and by bearings 34011 the rungs 32 at the other. The ends of the rungs are welded to the inner flanges of the sections 22, or otherwise secured thereon.

Referring to Fig. 10, the Ts 2| may also be built up from two hollow channels .25. 26 which are connected at their webs 21, for instance by welding. Referring to Figs. 10a and 1012, two hollow sections 25a and 26a may be placed end to end with their webs, and connected by welding or the like. A vertical stay may be dispensed with here or be replaced by a horizontal stay. -If a vertical stay 24a is provided it is equipped with tabs 24b at its upper and lower edges which are inserted in suitable holes in the flanges.

Referring to Figs. 11 and 15, the side pieces I are double-trapeze sections, being built up from two channel sections 30 and $9 toniake' up a hollowsection 31 with two central ridges, the rollers 53 on their pins I l in. sleeves 56 and bearings 58 on the base 51 of rungs 50, here shown as square tubes, being notched in conformity with the ridges. Rails 55 are secured to the outer sections 39 and rollers 54 on pins- 88 in the pillars 52 bear on them;

The side pieces may be braced by a vertical stay 42, or they may .be built up from two tubes 44, 45, with their longer webs 48 connected by welding or the like. Trapeze sections may be replaced by rectangular channel sections, 40, 41, Fig. 13, with avertical stay 43 between them. As shown in Fig. 14, two tubes of rectangular section 46, 41 may be connected by their webs 49.

Referring to Figs. 16 and 1'7, the side pieces are here built up from three rectangular tubes arranged in the shape of the letter 2. Fig. 19 s the side piece disassembled. It consists 'i "o and bent to a rectangle at one end, to a at the other. The flanges of the bars forming the rectangles are welded to their webs at and lid, respectively, and to each otfners webs at to, The webs 65 and form the stays for the sections. l3 are tubular braces connecting the side pieces I, and 12 are rollers on the braces which support the side pieces I. The lower flange of each side piece engages below the upper flange of the adjacent side piece, as shown at '30 and TI. Antif'iction liners may be inserted at these points.

14 are the rungs.

Referring to Fig. 18, the side pieces are built up from three independent square tubes 61, 6B, 69 which may be connected by welding.

The units interengage for a certain distance when the ladder is extended. seizing at these points must be avoided so that the units are readily displaced. To this end I provide rocking supports for the rollers at the inner ends of the units, and also for the rollers which engage the units from above, as shown in Figs. 20 to 24.

The sections of the side pieces 18, 85, Fig. 21, are the same as shown in Fig. 3. 19 is a pin secured partly in the section 18 and. partly in a bearing 8| on the base of a rung 82. 86 is a rocking arm, and 84, 84 are supporting rollers mounted to rotate about pins 83 at the ends of the arm. The rail 85, Fig. 21, of the lower secttion at each side piece runs on the rollers lit, 84. Any number of rollers may be arranged on a rocking arm.

The rollers which bear on the flanges Sl of the side pieces, Fig. 21, are also arranged at opposite ends of an arm t7 and mounted to rotate about pins 89 at the ends of the arm which in turn is mounted to. rock about a pin 93 in a pillar 92, or at any othersuitable point. Any number of rollers may be arranged on the arms M.

It will be understood from the foregoing description that my invention may be modified in various ways without departing from its gist, and in particular I wish to emphasize that I am not limited to any particular section, or combination of sections, nor to any particular method or means for connecting the sections to each other or to other members. Welding is generally preferred but the parts may also be riveted or secured in any other suitable manner. The sections may be obtained in any suitable way and may be commercial or special sections, as required.

Although a. ladder consisting of three parts is shown in the drawings, the invention is not restricted to this particular form but covers any constructional embodiment ot a ladder comprising a plurality parts.

I claim:

1. An extension. ladder comprising telescoping units, metal side pieces 0! closed hollow cross section built up of section elements on said units. bracing means in said side pieces, bearings spaced from said side pieces and secured to rungs, pins extending through said side pieces and bearings, and supporting rollers for the side piece arranged above said pins.

2. An extension ladder comprising telescoping units, metal side pieces of closed hollow cross section built up of section elements on said units, bracing means in said side pieces, supporting rollers on said side pieces on which the side pieceoi the next unit is carried, and rollers on rocking supports bearing on said side pieces from above.

3. An extension ladder comprising telescoping units, metal side pieces of closed hollow cross section on said units, rungs connecting said side pieces, bearing pins supported in said side pieces at one end, and on said rungs at the other end,v

= rocking arms on said pins, and rollers on said secured together by rungs and and bearings. and supp rting of said longitudinal prised of a longitudinal transverse bracing elearms for supporting the side piece oi the unit above. 1 p

4. An extension ladder comprising telescoping units, said units having two longitudinal elements each formed of a longitudinal bracing element and two longitudinal members cup-shaped in cross section, the edges of said members bracing element, bearings mounted on said rungs and spaced from said longitudinal elements, pins extending through said longitudinal members rollers mounted on said pins for the longitudinal elements of the adjacent -telescopic: section---oi the: extension ladder. a

5. An extension ladder comprising telescoping units. said units having longitudinal side elements'oi sheet metal connected byrungs, each side members being comment, an upper longitudinal member substantially in the form of an inverted U in cross seciion and a lower longitudinal member substantially U-shaped in cross-section, the end portions 0! said U-shaped members having outwardly extending bracing element, said upper inverted U-shaped member being provided at its apex with an inwardly extending portion adapted to form a guide for the flange on the inverted U-shaped being secured to said flanges secured to said longitudinal section of the adjacent telescopic section of the extension ladder.

' 6. An extension ladder comprising telescoping units, said units having longitudinal side elements the inverted U-shaped section of the longitudinal side member oi the adjacent telescopic section 0! the extension ladder, and rollers mounted adjacent the side pieces of each telescopic section and adapted to abut the U-shaped section of the side members'oi the adjacent telescopic section of the ladder.

'Z. An extension ladder comprising telescopic longitudinal side member of theunits, side pieces of closed hollow metal sections on said units, each 0! said side pieces being provided with a portion which extends substantially at the top beyond the plane of the side thereof to form a guide for the adjacent telescopic section of the ladder, said extending portions'overlapping a portion which extends irom.the adjacent section at a point intermediate the top and bottom of said adjacent section.

8. An extension ladder comprising telescopic units, side pieces oi'clos'ed hollow metal sections on said units. each or said side pieces being provided with aportion which extends substantially at the top beyond the plane oi. the side thereof to iorm a guide for the adjacent telescopic section of the ladder, said ,extended portion being WILHEIMADOLF HUMMEL. 

